New Wound Protocol Reduces Surgical-Site Infections After Cesarean Delivery

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Negative pressure wound therapy (NPWT) significantly lowers the risk of surgical-site infections after cesarean delivery in women who are morbidly obese, according to the results of a new study. Since the utilization of NPWT in January 2015 for all morbidly obese women undergoing cesarean delivery, the risk of postoperative infections has decreased by 60% in this high-risk group.

Margaret Villers, MD, a fellow in the Division of Maternal Fetal Medicine in the Department of Obstetrics and Gynecology at Duke University, presented results from the retrospective cohort study at the 37th Annual Pregnancy Meeting of the Society for Maternal Fetal Medicine held January 23 to 28, 2017, in Las Vegas, NV.

“One of the nice things about NPWT is that it doesn’t require antibiotics, so you don’t have to worry about antibiotic resistance,” Villers said. “Providers can consider this strategy for reducing cesarean delivery infections while remaining adherent to their antibiotic stewardship programs.”

Women who are morbidly obese experience the highest rate of surgical-site infections after cesarean delivery. Complications from surgical-site infections contribute to hospital readmission rates and substantial medical costs.

Although NPWT is a recognized tool for reducing wound complications, its role in the management of surgical-site infections after cesarean delivery has not yet been established. The study was designed to evaluate use of NPWT to reduce the rate of surgical-site infections following cesarean delivery in women who were morbidly obese.

The retrospective analysis included 317 pregnant women who underwent cesarean delivery between January 2014 and June 2016. All women had a median body mass index (BMI) of 40 kg/m² or higher at the time of delivery. During the first year of the study period, all patients received standard-care surgical dressing. Beginning in January 2015, Duke University Medical Center began using prophylactic NPWT on all morbidly obese women undergoing cesarean delivery. The NPWT dressing remained in place for 7 days following surgery.

The primary end point of the study was the rate of surgical-site infections, including superficial wound infections, deep wound infections, and endometritis, among women receiving either standard-care postoperative dressing (n = 107) or NPWT (n = 210). The secondary end point was the rate of all wound complications, including surgical-site infections, seroma, and hematoma.

Several baseline characteristics and procedural variables differed between the treatment groups. Compared with the standard-care group, women receiving NPWT had a higher median BMI at delivery, a higher rate of chorioamnionitis, and were more likely to receive vertical skin incisions  (Table 1). Conversely, suture skin closure was more common in the standard-care group than in the NPWT group.

Table 1. Patient and Procedural Characteristics

Characteristic  Standard Care
(n = 107)
NPWT
(n = 210)
P Value
Median BMI at delivery, kg/m² 44.6 48.2 < .001
Chorioamnionitis, % 1 10 .02
Vertical skin incisions, % 1 9 < .01
Suture skin closure, %  97 91 .04

BMI = body mass index, NPWT = negative pressure wound therapy, NS = nonsignificant.

Relative to standard care, NPWT demonstrated a significant benefit in terms of surgical outcomes (Table 2). The risk of surgical-site infections was 19% for those in the standard-care group compared with 6% for those in the NPWT group (P = .003). The overall risk of all wound complications also decreased from 22% in the standard-care group to 13% with NPWT (P < .001).

Table 2. Surgical Outcomes According to Wound Care Protocol

Outcome  Standard Care
(n = 107), %
NPWT
(n = 210), %
P Value
All surgical-site infections 19 6 .003
Superficial incisional 8 1
Deep incisional 4 3
Endometritis 6 1
All wound complications 22 13 < .001
Infections 19 6
Seroma 3 6
Hematoma 1 1

NPWT = negative pressure wound therapy.

The researchers also conducted a multivariable analysis to control for the baseline and procedural variations between the treatment groups. In the multivariable analysis, NPWT remained significantly associated with a 60% reduction in surgical-site infections compared with standard care (adjusted odds ratio 0.4; 95% confidence interval, 0.2-1.0). However, the association between NPWT and overall wound complications was no longer significant.

Overall, these findings support the use of NPWT to reduce the rate of surgical-site infections after cesarean delivery in women who are morbidly obese without relying on antibiotics in this high-risk patient population.

Source: Villers MS, Hopkins MK, Harris BS, Brancazio LR, Grotegut CA, Heine RP. Negative pressure wound therapy reduces cesarean delivery surgical site infections in morbidly obese women. Presented at: Society for Maternal-Fetal Medicine 37th Annual Pregnancy Meeting; January 23-28, 2017; Las Vegas, NV. Abstract 341.